"The table is set for dinner."
Translation:Akşam yemeği için masa kuruldu.
I don't know the formal term for it, but :
"to be" in simple present tense + past tense verb"
Is used in contexts of where the past event occurred like a few seconds to a few minutes ago in English. You can also try to milk it by going up to 12 hours ago.
General rule of thumb: Use "was" for yesterday's events, use simple present tense "to be" for the past few minutes.
edit: more info
miş has the effect that you are uncertain about what you are saying. It's a past tense of hearsay.
Akşam yemeği için masa kurulmuş = [it appears/it seems that/I think/They say] The table is set for dinner
Read this it is way more detailed in explaining this tense :http://www.turkishlanguage.co.uk/pasttense.htm